'Gwalch Cywyddau Gwŷr' : Ysgrifau ar Guto'r Glyn a Chymru'r Bymthegfed Ganrif = Essays on Guto'r Glyn and Fifteenth-Century Wales. ISBN 9781907029103. Published by Canolfan Uwchefrydiau Cymreig a Cheltaidd Prifysgol Cymru in 2013. Publication and catalogue information, links to buy online and reader comments.